You can always count on Elsie to Scripture references to anything.
As far as the Gap theory, what I’ve been told by someone who knows Hebrew is that there is a change in tense between the first two verses in Genesis. The first verse is that the universe was created, as in the creation of something new.
The second verse indicates a remaking of the earth, making it habitable for humans and life. Apparently the verb means that the earth became formless and void. The thinking is that there is no knowing what the time frame is between the first and second verses.
Not knowing Hebrew myself, I honestly have never investigated that.
Other people disagree with that interpretation.
The thing that makes it all so difficult is that there are Bible scholars who take both positions and present good cases for their side.
I blame it on that Timothy fellow!
2 Tim 4:2